physics ip cbse class 12

/ / 2016
ELECTROMAGNETICINDUCTION

INDEX
 Aim
 Certificate
 Acknowledgement
 Apparatus
 Introduction
 Theory

 Conclusion
 Bibliography

AIM
To determine the faraday’s law of
electromagnetic induction using a
copper wire wound over an iron rod and
astrong magnet.

CERTIFICATE
This is to certify that the PHYSICS project titled
‘ELECTROMAGNETIC INDUCTION’ has been
successfully completed by D.J SRI
VIGNESHWAR of Class XII in partial fulfillment
of curriculum of
CENTRAL BOARD OF SECONDARY EDUCATION
(CBSE) leading to the award of annual
examination of the year 2016-2017.
INTERNAL EXAMINER TEACHER IN-CHARGE

ACKNOWLEDGEMENT
It gives me great pleasure to express my
gratitude towards our Physics teacher
S.DEEPA LAKSHAMI for her guidance,
support and encouragement throughout the
duration of the project. Without her
motivation and help the successful
completion of this project would not have

APPARATUS
 Insulatedcopper wire
 A ironrod
 A strong magnetand
 A lightemittingdiode
(LED)

INTRODUCTION
Faraday's law of induction is a basic law
of electromagnetism that predicts how
a magnetic field will interact with
an electric circuit to produce
an electromotive force (EMF). It is the
fundamental operating principle

of transformers, inductors, and many
types
of electrical motors and generators.
Electromagnetic induction was
discovered independently by Michael

Faraday and Joseph Henry in 1831;
however, Faraday was the first to publish
the results of his experiments. Faraday
explained electromagnetic induction
using a concept he called force. These
equations for electromagnetic are
extremely important since they provide a
means to precisely describe how many
natural physical phenomena in our
universe arise and behave. The ability to
quantitatively describe physical
phenomena not only allows us to gain a
better understanding of our universe, but
it also makes possible a host of
technological innovations that define

modern society. Understanding
Faraday’s Law of Electromagnetic
Induction can be beneficial since so many
aspects of our daily life function because
of the principles behind Faraday’s Law.
From natural phenomena such as the
light we receive from the sun, to
technologies that improve our quality of
life such as electric power generation,
Faraday’s Law has a great impact on
many aspects of our lives.

Faraday’s Law is the result of the
experiments of the English chemist and
physicist Michael Faraday. The concept
of electromagnetic induction was
actually discovered simultaneously in

1831 by Faraday in London and Joseph
Henry, an American scientist working in
New York, but Faraday is credited for the
law since he published his work first. An
important aspect of the equation that
quantifies Faraday’s Law comes from the
work of Heinrich Lenz, a Russian physicist
who made his contribution to Faraday’s
Law, now known as Lenz’s Law, in 1834
(Institute of Chemistry).

Faraday’s law describes electromagnetic
induction, whereby an electric field is
induced, or generated, by a changing
magnetic field. Before expanding upon

this description, it is necessary to
develop an understanding of the concept
of fields, as well as the related concept of
potentials.
Faraday's first experimental
demonstration of electromagnetic
induction (August 29, 1831), he wrapped
two wires around opposite sides of an
iron ring or "torus" (an arrangement
similar to a modern toroidal
transformer) to induce current

Figur1 Faraday's First Experiment e
Some physicists have remarked that
Faraday's law is a single equation
describing two different phenomena:

the motional EMF generated by a
magnetic force on a moving wire
(see Lorentz force), and the transformer
EMF generated by an electric force due
to a changing magnetic field (due to the
Maxwell–Faraday equation). James Clerk
Maxwell drew attention to this fact in his
1861 paper On Physical Lines of Force. In
the latter half of part II of that paper,
Maxwell gives a separate physical
explanation for each of the two
phenomena. A reference to these two
aspects of electromagnetic induction is
made in some modern textbooks.

The magnetic flux (often denoted Φ or
ΦB) through a surface is the component
of the B field passing through that
surface. The SI unit of magnetic flux is
the Weber (Wb) (in derived units: volt-
seconds), and the CGS unit is
the Maxwell. Magnetic flux is usually
measured with a flux meter, which
contains measuring coils and electronics
that evaluates the change of voltage in
the measuring coils to calculate the
magnetic flux.
If the magnetic field is constant, the
magnetic flux passing through a surface
of vector area S is

Where B is the magnitude of the
magnetic field (the magnetic flux
density) having the unit of
Wb/m2 (Tesla), S is the area of the
surface, and θ is the angle between the
magnetic field lines and the normal
(perpendicular) to S.
For a varying magnetic field, we first
consider the magnetic flux through
infinitesimal area element dS, where we
may consider the field to be constant
:

From the definition of the magnetic
vector potential A and the fundamental
theorem of the curl the magnetic flux
may also be defined as:
Where the line integral is taken over the
boundary of the surface S, which is
denoted ∂S.
LAW:-
The most widespread version of
Faraday's law states:

The induced electromotive force in any closed
circuit is equal to the negative of the time
rate of change of the magnetic flux through
the circuit.
This version of Faraday's law strictly
holds only when the closed circuit is a
loop of infinitely thin wire, and is invalid
in other circumstances as
discussed below. A different version,
the Maxwell–Faraday
equation (discussed below), is valid in all
circumstances.
When the flux changes—
because B changes, or because the wire
loop is moved or deformed, or both—
Faraday's law of induction says that the

wire loop acquires an EMF , defined as
the energy available per unit charge that
travels once around the wire loop (the
unit of EMF is the volt).Equivalently, it is
the voltage that would be measured by
cutting the wire to create an open
circuit, and attaching a voltmeter to the
leads.
According to the Lorentz force law (in SI
units),
The EMF on a wire loop is:

where E is the electric field, B is
the magnetic field (aka magnetic flux
density, magnetic induction), dℓ is an
infinitesimal arc length along the wire,
and the line integral is evaluated along
the wire (along the curve the coincident
with the shape of the wire).
The Maxwell–Faraday equation states
that a time-varying magnetic field is

always accompanied by a spatially-
varying, non-conservative electric field,
and vice-versa. The Maxwell–Faraday
equation is
Where are the curl operator and
again E(r, t) is the electric field and B(r, t)
is the magnetic field. These fields can
generally be functions of position r and
time t.
The four Maxwell's equations (including
the Maxwell–Faraday equation), along
with the Lorentz force law, are a
sufficient foundation to

derive everything in classical. Therefore
it is possible to "prove" Faraday's law
starting with these equations. Faraday's
law could be taken as the starting point
and used to "prove" the Maxwell–
Faraday equation and/or other laws.)

CONCLUSION
Faraday’s Law of Electromagnetic
Induction, first observed and published
by Michael Faraday in the mid-
nineteenth century, describes a very
important electro-magnetic concept.
Although its mathematical
representations are cryptic, the essence
of Faraday’s is not hard to grasp: it
relates an induced electric potential or
voltage to a dynamic magnetic field. This
concept has many far-reaching
ramifications that touch our lives in

many ways: from the shining of the sun,
to the convenience of mobile
communications, to electricity to power
our homes.
We can all appreciate the profound
impact Faraday’s Law has on us.

BIBLIOGRAPHY
 WIKIPEDIA
 HOW STUFF WORKS
 SCIENCE FOR ALL
 WWW.ncert.nic.in

physics ip cbse class 12

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